Year, Volume, Issue, Page(s):15, 16, 15,
Study examined the effects of mental imagery-induced attention on pressure pain threshold and cortical plasticity using transcranial magnetic stimulation (TMS). Mental imagery is the process of envisioning specific physical or cognitive activities or perceptual experiences with the intention of altering the facilitation of neuronal networks. This blinded, randomized, and parallel-design trial comprised 30 healthy right-handed male subjects. Exploratory statistical analyses were performed using analysis of variance and t-tests for pain and TMS assessments. Pearson’s correlation was used to analyze the association between changes in pain threshold and cortical excitability. In the analysis of pain outcomes, there was no significant interaction effect on pain between group versus time. In an exploratory analysis, a significant effect of group was only observed for the targeted left hand. Although there was only a within-group effect of mental imagery on pain, further analyses showed a significant positive correlation of changes in pain threshold and cortical excitability (motor-evoked potentials via TMS). Results indicate that mental imagery has a minor effect on pain modulation in healthy subjects. Its effects appear to differ compared with chronic pain, leading to a small decrease in pain threshold. Assessments of cortical excitability confirmed that these effects are related to the modulation of pain-related cortical circuits. These exploratory findings suggest that neuronal plasticity is influenced by pain and that the mental imagery effects on pain depend on the state of central sensitization.